Healthcare Industry News:  antithrombin 

Biopharmaceuticals Licensing

 News Release - March 13, 2007

GTC Biotherapeutics Grants Expanded License to PharmAthene for Further Development of Protexia(R)

FRAMINGHAM, Mass.--(HSMN NewsFeed)--GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) and PharmAthene, Inc. have entered into an agreement providing PharmAthene an expanded license to GTC's patent rights, which will support the further development, manufacturing, regulatory approval and commercialization process for PharmAthene's Protexia® program. Protexia® is a recombinant form of human butyrylcholinesterase (rBChE) produced by PharmAthene in the milk of transgenic goats. PharmAthene is developing Protexia® as a pre- and post-exposure therapy for military or civilian victims of a chemical nerve agent attack. The expanded license agreement includes rights to utilize GTC's transgenic technology in the worldwide development and commercialization of Protexia® for all uses. This expanded license agreement follows the recently announced agreement under which GTC is providing PharmAthene clinical supply and manufacturing services for Protexia®. The financial terms of the expanded license agreement were not disclosed.

While the utility of human plasma derived butyrylcholinesterase (hBChE) to protect against nerve agent toxicity is well documented, a major limitation hindering its commercial development has been the inability to produce commercial quantities of hBChE due to a limited availability of appropriate blood supplies, low levels of the protein in plasma, and low production yields using traditional biotechnology methods. PharmAthene's recombinant hBChE overcomes these limitations by enabling substantially larger production yields than are possible using other expression systems or through purification of the native protein from human plasma. Transgenic production and manufacturing is estimated to be capable of supplying sufficient rBChE to make Protexia® available for use by the military and civilian populations.

About Nerve Agents

Organophosphate nerve agents, or anti-cholinesterase agents, cause toxicity by binding to and inhibiting acetylcholinesterase, an enzyme in the body that is essential for nervous system function. This leads to increases in acetylcholine and "cholinergic crisis" that can cause loss of muscle control, respiratory failure, paralysis, convulsions, permanent brain damage and eventually death.

These so-called nerve gases, which are actually all liquids at room temperature, are lethal in low quantities when inhaled or absorbed through the skin. Nerve agents can be classified as either G-agents (sarin, soman, tabun) or V agents (VX), both of which are exceedingly volatile and toxic.

About Protexia: Recombinant Human Butyrylcholinesterase

Protexia® is a form of recombinant human butyrylcholinesterase (rBChE), a potent organophosphate (OP) scavenger protein produced in the milk of transgenic goats, which is being developed for use as a prophylactic and therapeutic against acute organophosphate (OP) nerve agent toxicity. In September 2006 PharmAthene was awarded a multi-year contract valued at up to $213 million from the Department of Defense (DoD) U.S. Army Space and Missile Command, for advanced development of Protexia®.

About PharmAthene, Inc.

PharmAthene, a privately-held biotechnology company, was formed to meet the critical needs of the United States by developing biodefense products. PharmAthene is dedicated to the rapid development of important and novel biotherapeutics to address biological pathogens and chemicals that may be used as weapons of bioterror. PharmAthene's lead programs include Valortim(TM), a treatment for anthrax, and Protexia®, a treatment for nerve agent exposure. On January 22, 2007 PharmAthene announced that it had signed a definitive merger agreement with Healthcare Acquisition Corp, a publicly-traded special purpose acquisition company (AMEX: HAQ ). For more information on PharmAthene, please visit

About GTC Biotherapeutics, Inc.

GTC Biotherapeutics develops, produces, and commercializes therapeutic proteins through transgenic animal technology. In August 2006, ATryn®, GTC's recombinant form of human antithrombin, was approved by the European Commission for use in patients with hereditary antithrombin deficiency undergoing surgical procedures. This was the first approval anywhere in the world of a therapeutic protein produced from a transgenic animal.

GTC has also recently been granted a patent in the United States through 2021 for the production of any therapeutic protein in the milk of any transgenic mammal. GTC's transgenic production platform is particularly well suited to enabling cost effective development of proteins that are difficult to express in traditional recombinant production systems as well as those that are required in large volumes. Additional information is available on the GTC web site,

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, including without limitation statements regarding the development of downstream processing and transgenic production capacity for Protexia®, PharmAthene's plans for developing Protexia® for military and civilian markets, and plans for meeting the anticipated preclinical and clinical requirements for approval. Such forward-looking statements are subject to a number of risks, uncertainties and other factors that could cause actual results to differ materially from future results expressed or implied by such statements. Factors that may cause such differences include, but are not limited to, the risks and uncertainties discussed in GTC's most recent Annual Report on Form 10-K and its other periodic reports filed with the Securities and Exchange Commission, including the risks and uncertainties associated with the development of therapeutic proteins and dependence upon the actions of partners and regulatory and other governmental agencies. GTC cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this document, and GTC undertakes no obligation to update or revise the statements, except as may be required by law.

Source: GTC Biotherapeutics

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